GB1145192A - Magnetic telegraph recorder and transmitter - Google Patents

Abstract

1,145,192. Magnetic drum stores. INTERNATIONAL STANDARD ELECTRIC CORP. 3 March, 1967 [4 March, 1966], No. 10177/67. Heading G4C. [Also in Division H4] Serial data from a teleprinter is recorded on a drum store in parallel form, the position at which the parallel data is stored being determined by a counter-comparator arrangement. The serial data is converted to parallel and stored on bi-stable units. The start bit of each character data group causes a write counter to advance one step, e.g. to count n. The drum store comprises a clock track which gives a pulse for each character position. These clock pulses step a counter, reset at each revolution, and when the count reaches n a comparator opens gates to pass (in parallel bit form) the character stored on the bi-stable units to the write head; phase modulated coding may be used. The next character from the teleprinter will similarly be written in to position n + 1 on the drum. When a character is to be read from the drum a read counter is stepped, so indicating the position of the required character. When the clock counter shows the same count as the read counter the parallel data is read out from that position on the drum. The next character is read from the adjacent position. The read-out and write-in rates may differ.